Luck was on my side. Mom and I walk through the door. My SiL wasn't around because she was at a karate class. Meanwhile, Mom exclaimed, "Why did she leave one of those stinky candles burning on the kitchen table? She knows I can't stand the smell of them and won't be able to stay long!"
I smiled inside. My SiL is classic p_a. Mom asked and answered her own question and didn't realize it.